You don't need to reinstall the Synology package.
The DVR will update itself when new releases become available.
You can manually update it to the latest pre-release version by holding the Check for Updates button in the web UI.

We do not recommend upgrading the spk. There is no reason to as the dvr software updates itself. The spk is only used to bootstrap the initial update, and the changes were only to add support for more NAS models.